Explain reliability including the ways to assess/check it and how to improve reliability
Reliability is achieved when the results gained are consistent, reliability just means consistency
There are three ways to assess the reliability of an experiment/research:
Test-Retest method - this is where the same test is given to participants on separate occasions and then compared and if the two sets of scores are consistent it is said to be reliable. Important to keep large time gap between to reduce order effects
Inter observer method - used to assess reliability in an observation, the extent to which researchers agree on the behaviours being observed independently. If they have a consistent number of tallies agreed then it is said to be reliable
Split half method - this is used to see whether the items in a test/questionnaire are consistent with other items in the test. Items on one test are split into two and then the scores on each half are compared, if a high positive correlation is seen then the test is reliable
There are five ways to improve reliability which are:
1) Use standardised procedures
4) Standardised method for collecting data
5) Training for observers